Tuesday, 01 August, 2006

Drift mobility of long-living excitons in coupled GaAs qantum wells

The authors report on high-mobility transport of indirect excitons in coupled GaAs quantum wells. A voltage-tunable in-plane potential gradient is defined for excitons by exploiting the quantum confined Stark effect in combination with a lithographically designed resistive top gate. Excitonic photoluminescence resolved in space, energy, and time provides insight into the in-plane drift dynamics. Across several hundreds of microns an excitonic mobility of 105 cm2/eV s is observed for temperatures below 10 K. With increasing temperature the excitonic mobility decreases due to exciton-phonon scattering.